<html>
<head><meta charset="utf-8"><title>nightly std const generics · general · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/index.html">general</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html">nightly std const generics</a></h3>

<hr>

<base href="https://rust-lang.zulipchat.com">

<head><link href="https://rust-lang.github.io/zulip_archive/style.css" rel="stylesheet"></head>

<a name="203380235"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203380235" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203380235">(Jul 09 2020 at 12:42)</a>:</h4>
<p>hello!</p>
<p>besides required work effort, is there any other reason why const generics are not being taken advantage of inside the nightly std?</p>



<a name="203380329"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203380329" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203380329">(Jul 09 2020 at 12:43)</a>:</h4>
<p>They are</p>



<a name="203380383"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203380383" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203380383">(Jul 09 2020 at 12:44)</a>:</h4>
<p>Some array impls in libcore use const generics</p>



<a name="203380517"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203380517" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203380517">(Jul 09 2020 at 12:45)</a>:</h4>
<p>Apparently <a href="https://github.com/rust-lang/rust/blob/dbf3ae7c3beb5b493375bf76152e490b8cc81d1c/src/liballoc/lib.rs#L88">liballoc also uses const generics</a></p>



<a name="203380728"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203380728" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203380728">(Jul 09 2020 at 12:48)</a>:</h4>
<p>oh cool!</p>



<a name="203380848"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203380848" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203380848">(Jul 09 2020 at 12:49)</a>:</h4>
<p>I am curious which features exactly are permitted by const generics but I am guessing that's a bit hard of an information to get, or maybe the rust compiler can query all places where they are used</p>



<a name="203380907"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203380907" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203380907">(Jul 09 2020 at 12:49)</a>:</h4>
<p>I was under the impression that it would allow some revolutionary changes</p>



<a name="203381027"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381027" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Laurențiu <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381027">(Jul 09 2020 at 12:50)</a>:</h4>
<p>They can be used to e.g. offer some trait impls for arrays larger than 32 elements, but they're still disallowed just in case const generics fall off the table and are removed from the compiler (it would break user code that expects some trait to be implemented for a 33-element array).</p>



<a name="203381048"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381048" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Laurențiu <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381048">(Jul 09 2020 at 12:51)</a>:</h4>
<p>So until stabilization they can't be used for new functionality</p>



<a name="203381106"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381106" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381106">(Jul 09 2020 at 12:51)</a>:</h4>
<p>That's what I was suspecting heh</p>



<a name="203381195"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381195" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381195">(Jul 09 2020 at 12:52)</a>:</h4>
<p>But in nightly it should be OK? you're talking about stable right?</p>



<a name="203381291"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381291" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Laurențiu <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381291">(Jul 09 2020 at 12:53)</a>:</h4>
<p>But see <a href="https://github.com/rust-lang/rust/pull/74060">https://github.com/rust-lang/rust/pull/74060</a></p>



<a name="203381315"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381315" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Laurențiu <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381315">(Jul 09 2020 at 12:53)</a>:</h4>
<p>I think trait impls are always stable</p>



<a name="203381417"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381417" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381417">(Jul 09 2020 at 12:54)</a>:</h4>
<p><span class="user-mention silent" data-user-id="203546">Laurențiu Nicola</span> <a href="#narrow/stream/122651-general/topic/nightly.20std.20const.20generics/near/203381315">said</a>:</p>
<blockquote>
<p>I think trait impls are always stable</p>
</blockquote>
<p>I think I've seen <code>#[unstable]</code> applied to trait impls, but I'm not sure</p>



<a name="203381463"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381463" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381463">(Jul 09 2020 at 12:54)</a>:</h4>
<p><span class="user-mention silent" data-user-id="203546">Laurențiu Nicola</span> <a href="#narrow/stream/122651-general/topic/nightly.20std.20const.20generics/near/203381315">said</a>:</p>
<blockquote>
<p>I think trait impls are always stable</p>
</blockquote>
<p>I very strongly believe all impls of stable traits are insta stable</p>



<a name="203381491"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381491" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381491">(Jul 09 2020 at 12:55)</a>:</h4>
<p>unstable traits can and should have unstable impls though afaik</p>



<a name="203381616"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381616" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381616">(Jul 09 2020 at 12:56)</a>:</h4>
<blockquote>
<p>besides required work effort, is there any other reason why const generics are not being taken advantage of inside the nightly std?</p>
</blockquote>
<p>Because they are still nearly unusable for anything except trait impls rn</p>



<a name="203381662"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381662" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381662">(Jul 09 2020 at 12:56)</a>:</h4>
<p>the big next step (at least my current plan) is landing <a href="https://github.com/rust-lang/rust/pull/74113">https://github.com/rust-lang/rust/pull/74113</a></p>



<a name="203381683"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381683" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381683">(Jul 09 2020 at 12:56)</a>:</h4>
<p>Okay, I can see that, I believed their design was more certain, apparently not</p>



<a name="203381706"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381706" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381706">(Jul 09 2020 at 12:57)</a>:</h4>
<p>at this point const generics in methods actually work without causing an ICE</p>



<a name="203381842"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381842" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381842">(Jul 09 2020 at 12:58)</a>:</h4>
<p>and we can then add the new unstable methods <code>array_chunks</code> + <code>array_windows</code> which will so guuuuud</p>



<a name="203381856"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381856" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381856">(Jul 09 2020 at 12:58)</a>:</h4>
<p>yes!</p>



<a name="203381930"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381930" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381930">(Jul 09 2020 at 12:59)</a>:</h4>
<p>I really want to write</p>
<div class="codehilite"><pre><span></span><code><span class="kd">let</span><span class="w"> </span><span class="n">slice</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">&amp;</span><span class="p">[</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p">,</span><span class="w"> </span><span class="mi">4</span><span class="p">,</span><span class="w"> </span><span class="mi">5</span><span class="p">,</span><span class="w"> </span><span class="mi">6</span><span class="p">,</span><span class="w"> </span><span class="mi">7</span><span class="p">];</span><span class="w"></span>
<span class="k">for</span><span class="w"> </span><span class="o">&amp;</span><span class="p">[</span><span class="n">lhs</span><span class="p">,</span><span class="w"> </span><span class="n">rhs</span><span class="p">]</span><span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="n">slice</span><span class="p">.</span><span class="n">array_windows</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="n">assert_eq</span><span class="o">!</span><span class="p">(</span><span class="n">lhs</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="n">rhs</span><span class="p">);</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
</code></pre></div>



<a name="203381935"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203381935" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203381935">(Jul 09 2020 at 12:59)</a>:</h4>
<p>I feel like I should start contributing to the compiler because all the frustrations I've had I could at least feel like I had power to overcome them, but it feels daunting from here</p>



<a name="203382080"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203382080" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203382080">(Jul 09 2020 at 13:00)</a>:</h4>
<p>Thanks for updating me</p>



<a name="203382085"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203382085" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203382085">(Jul 09 2020 at 13:00)</a>:</h4>
<p>There are always simple issues which don't require a lot of knowledge to get you started <span aria-label="sparkles" class="emoji emoji-2728" role="img" title="sparkles">:sparkles:</span></p>



<a name="203382303"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203382303" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203382303">(Jul 09 2020 at 13:02)</a>:</h4>
<p>Also the compiler team will be able to answer your questions if you have any</p>



<a name="203382310"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203382310" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203382310">(Jul 09 2020 at 13:02)</a>:</h4>
<p>Ahah I'll have to start with that I am certain - however probably the most interesting would be hard to achieve!</p>



<a name="203382497"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203382497" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203382497">(Jul 09 2020 at 13:04)</a>:</h4>
<p>Well I think your most important resource is time, time to dive into the code, understand how it works, experiment with it, make mistakes, repair them etc...</p>



<a name="203382509"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203382509" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203382509">(Jul 09 2020 at 13:04)</a>:</h4>
<p>Ah, and time to compile rustc too <span aria-label="grinning face with smiling eyes" class="emoji emoji-1f601" role="img" title="grinning face with smiling eyes">:grinning_face_with_smiling_eyes:</span></p>



<a name="203382724"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203382724" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Laurențiu <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203382724">(Jul 09 2020 at 13:06)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AE-easy">https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3AE-easy</a> might help :-)</p>



<a name="203382812"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203382812" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203382812">(Jul 09 2020 at 13:07)</a>:</h4>
<p>Also, issues around const generics are labeled <code>F-const_generics</code>... and there are 68 of them</p>



<a name="203382907"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203382907" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203382907">(Jul 09 2020 at 13:08)</a>:</h4>
<p><span class="user-mention silent" data-user-id="255061">LeSeulArtichaut</span> <a href="#narrow/stream/122651-general/topic/nightly.20std.20const.20generics/near/203382812">said</a>:</p>
<blockquote>
<p>Also, issues around const generics are labeled <code>F-const_generics</code>... and there are 68 of them</p>
</blockquote>
<p>I can't really recommend looking through them to find interesting things to work with <span aria-label="sweat smile" class="emoji emoji-1f605" role="img" title="sweat smile">:sweat_smile:</span></p>



<a name="203383017"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203383017" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203383017">(Jul 09 2020 at 13:09)</a>:</h4>
<p>if you want to work on const generics it's a lot simpler to ask me directly <span aria-label="laughing" class="emoji emoji-1f606" role="img" title="laughing">:laughing:</span> (or <span class="user-mention silent" data-user-id="121053">varkor</span> and <span class="user-mention silent" data-user-id="119009">eddyb</span> )</p>



<a name="203383123"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203383123" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203383123">(Jul 09 2020 at 13:10)</a>:</h4>
<p>most of the remaining const generics issues tend to either be blocked on <a href="https://github.com/rust-lang/rust/pull/74113">https://github.com/rust-lang/rust/pull/74113</a> or are partially outdated</p>



<a name="203383205"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203383205" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203383205">(Jul 09 2020 at 13:11)</a>:</h4>
<p>i really should just take some time once <a href="https://github.com/rust-lang/rust/issues/74113">#74113</a> lands to go through all open const generics issues to see what is actually still relevant :/</p>



<a name="203394093"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203394093" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203394093">(Jul 09 2020 at 14:42)</a>:</h4>
<p>Thanks a lot for all the guidance!</p>



<a name="203394159"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203394159" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203394159">(Jul 09 2020 at 14:43)</a>:</h4>
<p>Time to compile rustc, well it compiles incrementally, doesnt it?</p>



<a name="203394194"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203394194" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203394194">(Jul 09 2020 at 14:43)</a>:</h4>
<p>Yes, it does if you pass the <code>-i</code> flag</p>



<a name="203394215"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203394215" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203394215">(Jul 09 2020 at 14:43)</a>:</h4>
<p>You can find guidance in the rustc-dev-guide</p>



<a name="203394280"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203394280" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203394280">(Jul 09 2020 at 14:43)</a>:</h4>
<p>Also I was thinking, is the caching for rustc CI system top notch?</p>



<a name="203394361"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203394361" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203394361">(Jul 09 2020 at 14:44)</a>:</h4>
<p>Can it cache across jobs of different rustc versions?</p>



<a name="203394425"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203394425" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203394425">(Jul 09 2020 at 14:44)</a>:</h4>
<p>I think caching intermediate compilation results is a real topic with CI systems in general, they waste so much energy currently!</p>



<a name="203394498"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203394498" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203394498">(Jul 09 2020 at 14:45)</a>:</h4>
<p>(You should check out the new <a href="https://rustc-dev-guide.rust-lang.org/getting-started.html">getting started</a> chapter)</p>



<a name="203394699"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203394699" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203394699">(Jul 09 2020 at 14:46)</a>:</h4>
<p>I am thinking it would need deep integration with the compiler to be done properly, considering caching forward and backward version changes, maybe integrate with git so that if you cherry-pick a commit onto a branch, it takes an existing cache as close as possible to the change</p>



<a name="203394753"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203394753" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203394753">(Jul 09 2020 at 14:47)</a>:</h4>
<p>I remember reading there already! Thanks</p>



<a name="203395051"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203395051" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203395051">(Jul 09 2020 at 14:49)</a>:</h4>
<p><span class="user-mention" data-user-id="214522">@Leo Le Bouter</span> If you are interested in that, I’d look at sccache.</p>



<a name="203396374"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203396374" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203396374">(Jul 09 2020 at 14:58)</a>:</h4>
<p><span class="user-mention" data-user-id="116155">@Jake Goulding</span> I'll have a deeper look, I know about it but I don't think it goes that far</p>



<a name="203459396"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203459396" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203459396">(Jul 10 2020 at 00:55)</a>:</h4>
<p>"Please ask questions! A lot of people report feeling that they are "wasting expert time", but nobody on t-compiler feels this way. Contributors are important to us."</p>
<p>Yes I feel that way a lot too..</p>



<a name="203459455"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203459455" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Leo Le Bouter <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203459455">(Jul 10 2020 at 00:56)</a>:</h4>
<p>I consider myself an expert in other topics and often it freezes my progress when I have to explain the world to curious minds</p>



<a name="203473361"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/203473361" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#203473361">(Jul 10 2020 at 06:28)</a>:</h4>
<p>See <a href="#narrow/stream/131828-t-compiler/topic/a.20metaquestion/near/199106963">https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/a.20metaquestion/near/199106963</a> on where this note was discussed.</p>



<a name="204070658"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/nightly%20std%20const%20generics/near/204070658" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/nightly.20std.20const.20generics.html#204070658">(Jul 16 2020 at 11:18)</a>:</h4>
<p><span class="user-mention silent" data-user-id="216206">lcnr</span> <a href="#narrow/stream/122651-general/topic/nightly.20std.20const.20generics/near/203383205">said</a>:</p>
<blockquote>
<p>i really should just take some time once <a href="https://github.com/rust-lang/rust/issues/74113">#74113</a> lands to go through all open const generics issues to see what is actually still relevant :/</p>
</blockquote>
<p><a href="https://github.com/rust-lang/rust/pull/74392">https://github.com/rust-lang/rust/pull/74392</a></p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
</html>